Model x20-dsl and 2 x x20 (unable to pout this information into model field)

X20-dsl is vdsl connected

x20 is hardwired direct to x20-dsl

other x20 is connected over w-fi

Wi-Fi - both main and guest enabled.

Unable to connect IoT devices to hardwired x20 guest network just times out no errors, all other Decos no problem connecting with connecting devices to guest.

On hardwired deco x20 can connect anything to main Wi-Fi network.

Deco network operation mode is DSL-modem router.

all firmware is up to date

homeshield pro enabled

Help!